Premier Mark McGowan said the trip delivered on an election promise to promote WA around the world and secure jobs and opportunities for citizens.

"I took 40 people - vice chancellors, tourism experts - go and ask them whether they think it was worthwhile. They got access that they've never had before," he told reporters on Wednesday.

"We met with major airlines, government representatives, tourism providers, companies that provide support to foreign students (and) I met with the alumni of WA universities living in China."

Mr McGowan said without WA's relationship with China, Australia's trading situation would be "diabolical", adding federal Foreign Affairs Minister Julie Bishop had not been to China in the past two years.

"We sell, as a state, to China each and every year more than $60 billion worth of products - we purchase from them around $5 billion worth of products," the premier said.

He also labelled the Liberal state opposition "pathetic" for trying to score political points by criticising the trip.

AAP is seeking comment from the state government about whether the other 24 people who travelled to Asia paid their own way.